Design, Construction and Testing of Freeze Concentrator

The main aspects of this study, were the design, construction and performance of a freeze concentrator. The design process consists of three main parts: a vertical tube heat exchanger, an auger to scrape the ice formed and a refrigeration unit to bring the temperature to below freezing. Basically, the freeze concentration process used involves ice formation from a juice solution at the surface of a vertical tube heat exchanger. The ice will be scraped by a rotating auger, which pushes it out through a window and collected in a reservoir. This results in a product of higher solute concentration than its concentration in the feed. The potential application of the freeze concentrator was experimented using sugar solutions at three different feed concentrations i.e. 7.5%, 10.3% and 12% brix, as well as pineapple juice at 11.4% brix. The freezing point depression for the solutions were respectively -l.O7°C, -l.15°C, -1.49°C and -1.49°C. The feed flow rates used for the solutions were respectively 0.65 Vmin, 0.5 Vmin, 0.43 Vmin and 0.45 Vmin. Using these process parameters, the total mass of ice after 180 min is 1.75kg for a feed of 7.5% brix and 1.46kg for a feed of 12% brix. From theoretical analysis, the expected total mass of ice produced is 2.6kg for the 7.5% brix and 1.97kg for the 12% brix solution. Therefore, the performance efficiency for the freeze concentrator is around 67% of theory for all three sugar solutions. Base on the heat balance analysis, the overall thermal performance of this freeze concentration process for the three different feed concentrations shows that about 80010 of the refrigeration load is loss. If these losses were not considered, about 87% of the cooling energy transferred is for sensible heat removal and 13% for ice formation

Enzymatic rettings of green pepper berries for white pepper production

This study is carried out to determine the physical properties of green pepper berries and to improve the existing retting technique in white pepper production using the Viscozyme and Celluclast as the enzymes. Effects of blanched and non-blanched pepper berries, acidic solution and non-acidic solution, and different temperature of 28, 35, 42, and 49°C are determined to obtain the optimum conditions for enzymatic retting. The physical properties of green pepper berries such as dimension (5.21 mm), weight (0.11 g per berry), true density (1319.33 kg/m3), bulk density (596.9 kg/m3), sphericity (0.976), angle of repose (6.87°) and flow ability with funnel flow time of 5.27 seconds were determined. The enzymatic retting in 42oC can fully soften the pericarp of pepper berries from 15 days to 7 days. The enzymatic decortication has the efficiency in acidic solution (pH 4) and temperature of 42°C with non-blanched pepper berries. The enzymatic retting reached constant fracture force (20.98N) at the ninth soaking days while the non-enzymatic retting reached constant fracture force (21.89N) at the fifteenth soaking days

Development and testing of a Jatropha fruit shelling process for shell-free kernel recovery in biodiesel production

Achieving shell-free kernel recovery from Jatropha fruits is important to improve oil yield and oil quality during oil extraction in biodiesel production. A shelling process with two stages of cracking and separation to remove the shells completely and husks partially was designed. Both stages used double-level cracking rollers and a blower with ducting as a separation unit. For the first, the performance was evaluated using five different roller clearances (9.5 mm, 10.0 mm, 10.5 mm, 11.0 mm and 11.5 mm) with a combination of five blower air speeds (8.5 ± 0.5 m s−1, 9.0 ± 0.6 m s−1, 9.5 ± 0.5 m s−1, 10.0 ± 0.4 m s−1 and 10.5 ± 0.5 m s−1). A roller clearance of 10.5 mm and air speed of 10.0 ± 0.4 m s−1 were selected as the optimal conditions with the highest separation efficiency between kernels and shells at 94.59%. The shells and husks achieved 95.88% and 12.20% removal respectively while kernel recovery achieved 98.65%. For the second stage, the performance was evaluated using five different roller clearances (5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm and 7.0 mm) with a combination of five blower air speeds (6.5 ± 0.4 m s−1, 7.0 ± 0.2 m s−1, 7.5 ± 0.4 m s−1, 8.0 ± 0.2 m s−1 and 8.5 ± 0.5 m s−1). At the optimal conditions, with a roller clearance of 6.0 mm and air speed of 7.5 ± 0.4 m s−1, the maximum separation efficiency was 97.69%. Total shell and husk removal achieved for the stages were 100.00% and 45.46% respectively. A total of 2.40% kernels were lost

Mass modeling of Malaysian varieties pomelo fruit (Citrus Grandis L. Osbeck) with some physical characteristics

Knowledge of physical characteristics of Malaysian variety pomelo fruits are necessary for the design of some post harvesting, processing systems such as cleaning, handling, grading and packaging system. For proper development of pomelo grading systems, important relationships between the mass and some physical characteristics of pomelo fruits such as length, width, thickness, surface area, projected areas and volumes must be known. The aim of this research was to measure physical characteristics of two Malaysian varieties of pomelo fruit; Ledang (PO55) and Tambun (PO52) varieties. In this study, the mass of pomelo fruit was evaluated and correlated to measure physical characteristics using Linear, Quadratic, S-curve and Power models. The results showed that the correlation of the mass of pomelo fruit with all measured physical characteristics was significant at the 0.01 probability level. In the nutshell, mass modeling of pomelo fruit for Ledang (PO55) and Tambun (PO52) varieties based on the projected area are recommended according to economical view

Physical properties of Liberica coffee (Coffea liberica) berries and beans

Liberica coffee is the most important coffee species grown in Malaysia. However, there is little or no research at all conducted on coffee berries and green coffee beans since the plant itself is a low income crop in Malaysia. Therefore, research on Malaysian Liberica coffee can help to increase the knowledge of coffee farmers and coffee manufacturers in the processing and handling of the coffee. Physical properties of Liberica coffee berries and beans were investigated the current study. The properties investigated include the size, mass, density, coefficient of friction, angle of repose, fracture force and colour. In comparison to Arabica and Robusta coffee, Liberica coffee has the biggest size, mass, true density and fracture force values but were lower in bulk density in both berries and beans. The Liberica berries and beans were found to be orange-ish and yellowish colour respectively. Angle of repose was low and approximately similar in berries and beans while jute fibre gave the highest friction to both Liberica berries and beans

Effect of blending ratio on quality of fresh pineapple (Ananas comosus L.) and mango (Mangifera indica L.) juice blends

Quality and alimental contents of single fruit juice can be ameliorated through mixing or blending process with other fruit juices. Pineapple and mango are the most popular tropical fruits in Malaysia with good characteristic taste. Color properties of pineapple and mango juice blends at ratio of 70P:30M; 50P:50M; 30P:70M was evaluated in term of L*, a*, b* hue, Chroma, color difference (ΔE). Blends ratio 70P:30M juice give the best color performance in terms of hue, chroma and ΔE. Physicochemical properties of juice blends ratio of 70P:30M also give more perishable results of pH (4.32) titratable acidity (0.66% malic acid), total soluble solid (13.67), vitamin C (54.25 mg ascorbic acid/100 ml), and turbidity (438 NTU)

Effects of UVC irradiation and thermal treatment on the physico-chemical properties and microbial reduction of clear and turbid tamarind juice

Tamarind juice is commonly treated with thermal treatment to inactivate microorganisms. However, thermal treatment deteriorates the appearance and flavor of tamarind juice. In this study, the performance of UVC treatment on clear and turbid tamarind juice as an alternative to thermal treatment was investigated. Results showed that UVC treatment was able to reduce E. coli O157:H7 by 7-log reduction but unable to completely remove the total bacterial population as observed in thermally treated clear and turbid tamarind juices. The pH of treated tamarind juices was comparable to each other. Nonetheless, UVC treatment caused significant changes on the flavor of the juice as it significantly reduced the total soluble solids of tamarind juices and decreased the titratable acidity of turbid tamarind juice. However, UVC treatments retained the appearance i.e. turbidity and color of tamarind juices better than thermal treatment

Quality attributes of fresh pineapple-mango juice blend during storage

Blending or mixing two or more of fruit juices is able to improve the quality of juices as compared to single flavour. Pineapple and mango are among the popular tropical fruits in Malaysia. Despite the massive production of pineapple in Malaysia, utilisation of pineapple as a juice remains unpopular due to its exotic and strong flavour. Blending of pineapple with mango is believed to overcome this issue. Nevertheless, suitable blending ratios play important role in the end product quality. The present work aims to determine the physicochemical and nutritional quality of fresh blended pineapple-mango juice at different blending ratios for 25 days of refrigerated storage (4 ± 2°C). Physicochemical (colour, pH, titratable acidity, and total soluble solid) and nutritional (vitamin C, total phenolic content, and total antioxidant content) properties of fresh pineapple-mango juice blends of ratio 80% pineapple with 20% mango (R80:20) and 50% pineapple with 50% mango (50:50) were determined throughout 25 days of storage. Pineapple-mango juice blends at blending ratio of R80:20 exhibited better qualities in term of colour (lightness, chroma, hue, and browning index), chemical composition, and nutritional content

Dimension and stackability of cassava (Manihot esculanta Crantz) chips for mass production

Cassava chips that exist in the current market have no standardisation and cannot be stacked nicely into cylindrical container. The objectives of this work are to determine the different dimension of cassava chips produced with different thickness and to develop stackable chips during mass production. Fresh cassava tubers were harvested, washed, peeled and sliced. The thickness measurements used were 1.0 mm, 1.5 mm, 1.75 mm and 2.0 mm and 1.27 mm thickness was measured from commercial potato chips as a controlled sample. Then, it was fried in deep fat fryer with the temperature of 170°C. For each thickness studied, different numbers of slice (10, 20, 30 and 40 slices) were fried simultaneously. Results showed that there are 6 shapes of fried chips produced during the frying. To conclude, thickness of the slice and number of slices fried simultaneously give impact towards the shape of fried chip

Performance of UV pasteurization with quartz glass sleeve on physicochemical properties and microbial activity of pineapple juice

Quartz glass has characteristics of high purity, high thermal resistance, high resistivity and high dielectric strength. Currently, majority of research in this area is discussing about the UV reactor equipped by a quartz glass sleeve. The aim of this research is to investigate the effect of quartz glass sleeve on the physicochemical properties and microbial activity of pineapple fruit juice during storage. UV-C radiation is one of the nonthermal technologies that have been introduced in the food industry. UV-C has the advantage of no known toxic or significant nontoxic by-products formed during treatment. The UV reactor that is enclosed by quartz glass can maintain the quality of pineapple juice in terms of color (L* value, chroma and hue angle), total soluble solids, pH and ascorbic acid content. All of the physicochemical properties of pineapple juice underwent significant changes with storage time. Moreover, the UV reactor that is enclosed by quartz glass is able to extend the shelf life of juice for up to 5 weeks and achieve a 5 log reduction of Salmonella typhimurium in the juice after treatment